Background and Purpose
The preschool years (2.9–5 years) have been identified as a critical time to intervene on physical activity (PA), since children begin to form their PA habits during this time frame (1). To date, most of PA studies have focused on changing the outdoor play environment and have rarely focused on changing the PA level during the classroom setting. Additionally, most studies do not take into account the intermittent nature of preschoolers play patterns (2). A recent review of the literature indicates that the duration of most PA interventions in preschoolers ranges between 30 - 45 minutes per session (3). There is research that suggests that these long duration PA interventions may not be effective for young children. Within a 30-minute recess period, most children tend to accumulate the majority of their moderate-to-vigorous PA (MVPA) during the first 10 minutes of play, with the remaining 20 minute spent in sedentary to light intensity activities (4). The longer children participate in a given game or activity (structured or unstructured), the less activity they accumulate during the entire period of the activity (4). Shorter bouts in PA (e.g. <= 10 minutes in duration per session) have been shown to be a successful strategy for improving children’s PA, body weight, and academic performance (5-7). The majority of these studies have been in elementary school age children. The intermittent nature of preschoolers’ play patterns suggests that short bouts of activity implemented during the preschool day may be beneficial to PA levels.

Objectives
This study examined the effects of short bouts of structured PA (SBS-PA) implemented within the classroom setting as part of designated gross-motor playtime on during-school PA in preschoolers.

Methods
The Short bouTs of Exercise for Preschoolers (STEP) study was a six-month cluster-randomized study. Ten preschool centers serving low-income families were randomized to receive the SBS-PA (n=5) intervention or continue to follow their usual preschool center gross motor playtime activities (unstructured PA (UPA), n=5). Preschool centers were stratified by school size. Although all children within a preschool were exposed to the assigned study condition (SBS-PA or UPA), children within each preschool center were separately recruited to participate in study-related PA assessments. Children were not eligible to participate in PA assessments if they had a condition limiting their participation in MVPA, a condition limiting participation in other portions of the assessment, or if their parent/guardian was unable to read, understand, or complete the informed consent.

The Tutti Fruitti Instant Recess (TFIR) intervention was adapted for preschoolers from the Instant Recess® (IR) program originally designed for adults (11,12).  TFIR is 10-minute PA routines that are designed to engage participates in MVPA by engaging major muscle groups in the upper and lower body. TFIR routines, which are available on DVD, are set to music and designed to be led by teachers (who are watching the video); preschool students follow the teachers rather than watching the video. For the current study, teachers were instructed to implement TFIR during the first 10 minutes of their usual 30-minute gross motor playtime.  For the remaining 20 minutes students engaged in unstructured play. Sixteen TFIR DVDs were rotated weekly throughout the 6-month study; each video was viewed for a total of three weeks during the course of the study. The UPA consisted of traditional long bouts (30?minutes) of unstructured gross motor playtime with typical play equipment. SBS-PA and UPA teachers were asked to repeat their assigned intervention during the morning and afternoon gross motor playtimes, five days/week for six months. Children’s PA was assessed with accelerometers (Actigraph) and direct observation (Observational System for Recording Physical Activity in Children-Preschool Version (OSRAC-P)).

Results
Data was collected in 291 participants (SBS-PA, n=141; UPA, n=150). Participants were 4.1±0.8 years of age with BMI percentile of 68.5 ± 26.7. Study fidelity data indicated that classroom teachers only partially implemented the study as designed. Approximately, 95% of SBS-PA classroom teachers implemented the TFIR DVDs during the first 10 minutes of gross motor playtime. However, only 49% of the SBS-PA classroom implemented the 20-minute gross motor (free playtime) portion of the intervention following TFIR. When gross motor time was implemented it lasted for less than 20 minutes. Compared to baseline, intervals spent in light activity significantly increased in SBS-PA group but did not change in the UPA group. In the SBS-PA group, percent of intervals spent in MVPA increased from baseline to 3-months then decreased at 6-months to baseline values. In the UPA group, percent of intervals in MVPA decreased between baseline and 3-months then increased back to baseline values at 6-months. Significant group by visit interaction was observed for percent time spent in total preschool day MVPA.

Conclusions
The implementation of short bouts of PA can potentially improve preschoolers PA during their classroom setting.

Implications for Practice and Policy
Preschool PA policies needs to be set taking into account the intermittent nature of preschoolers’ play patterns.

References

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Support / Funding Source
This work was supported by Robert Wood Johnson Foundation, Active Living Research Grant # 68509.